Http_long_poll_cmd.java

/*
XOWA: the XOWA Offline Wiki Application
Copyright (C) 2012-2017 gnosygnu@gmail.com

XOWA is licensed under the terms of the General Public License (GPL) Version 3,
or alternatively under the terms of the Apache License Version 2.0.

You may use XOWA according to either of these licenses as is most appropriate
for your project on a case-by-case basis.

The terms of each license can be found in the source code repository:

GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
*/
package gplx.xowa.addons.servers.https; import gplx.*; import gplx.xowa.*; import gplx.xowa.addons.*; import gplx.xowa.addons.servers.*;
import gplx.core.envs.*;
public class Http_long_poll_cmd implements gplx.xowa.htmls.bridges.Bridge_cmd_itm {
	private final    List_adp msgs = List_adp_.New();
	private boolean active;

	public void Init_by_app(Xoa_app app) {
		app.Gui__cbk_mgr().Reg(Xog_cbk_wkr__http.Instance);
	}
	public void Send_msg(String msg) {
		synchronized (msgs) {
			msgs.Add(msg);
		}
	}
	public String Exec(gplx.langs.jsons.Json_nde data) {
		// NOTE: this class is a singleton and only supports one user; need to track multiple requests by having http_server track incoming users
		synchronized (msgs) {
			if (active) return "polling";
		}
		// check if already active; if so, return;
		while (true) {
			// get msgs in queue
			int msgs_len = 0;
			synchronized (msgs) {
				active = true;
				msgs_len = msgs.Len();
			}

			// no messages
			if (msgs_len == 0) {
				gplx.core.threads.Thread_adp_.Sleep(Sleep_interval);
				continue;
			}

			// message found; exit loop;
			break;
		}

		// return commands
		String[] rv = null;
		synchronized (msgs) {
			rv = msgs.To_str_ary_and_clear();
			active = false;
		}
		return String_.Concat_lines_nl(rv);
	}

	public byte[] Key() {return BRIDGE_KEY;} private static final    byte[] BRIDGE_KEY = Bry_.new_a7("long_poll");
        public static final    Http_long_poll_cmd Instance = new Http_long_poll_cmd(); Http_long_poll_cmd() {}

	private static final int 
	  Sleep_interval	= 100
	;
}